Galaxies are complex systems of stars, gas and dust swirling together to the tune of gravity . These three ingredients emit light at different colors or wavelengths; most of this radiation is invisible to the human eye, but it can be detected with specialized instruments. By assigning colors to these data and combining them we can produce impressive images of galaxies . This article is intended to help you understand the physics behind these images, so that you can appreciate them under a completely different new light.
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